EP3996332A1

EP3996332A1 - Control apparatus, control method, computer-readable medium, and communication system

Info

Publication number: EP3996332A1
Application number: EP21191673.9A
Authority: EP
Inventors: Keiichi Teramoto
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 2020-11-04
Filing date: 2021-08-17
Publication date: 2022-05-11
Anticipated expiration: 2041-08-17
Also published as: JP7500390B2; EP3996332B1; JP2022074263A

Abstract

A control apparatus (100) includes a device controller (101), a calculator (102), and a communication controller (103). The device controller (101) generates a command for controlling operation of an intended device (300; 300-2). The calculator (102) calculates an estimated value of an operation delay time according to classification information representing at least one of a type of the command and a type of a state transition of the device in operation following the command. The operation delay time is a length of time from when the device receives the command to when the device completes a state transition after the operation following the command. The communication controller (103) transmits the command to the device so that the device completes the state transition after the operation following the command at time adjusted in accordance with the estimated value.

Description

FIELD

The present disclosure relates to a control apparatus, a control method, a computer-readable medium, and a communication system.

BACKGROUND

Systems are known, which include a control apparatus, such as a server, for controlling a plurality of devices installed in a remote location. It may be preferable for such a system to control the operation timing of the devices more accurately, for example, to control the devices to start operating at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of an overall configuration of a communication system including a control apparatus according to an arrangement;
FIG. 2 is a diagram of an overall configuration of a communication system including a control apparatus according to an arrangement;
FIG. 3 is a block diagram of apparatuses and a device according to a first arrangement;
FIG. 4 is a diagram illustrating a communication delay and an operation delay in a control command;
FIG. 5 is a diagram illustrating exemplary calculation information for use in calculating an estimated value;
FIG. 6 is a flowchart of control processing according to the first arrangement;
FIG. 7 is a block diagram of apparatuses and a device according to a second arrangement;
FIG. 8 is a sequence diagram of control processing according to the second arrangement; and
FIG. 9 is a hardware configuration diagram of an apparatus according to an arrangement.

DETAILED DESCRIPTION

According to an arrangement, a control apparatus includes a device controller configured to generate a command for controlling operation of an intended device; a calculator configured to calculate an estimated value of an operation delay time according to classification information representing at least one of a type of the command and a type of a state transition of the device in operation following the command, the operation delay time being a length of time from when the device receives the command to when the device completes a state transition after the operation following the command; and a communication controller configured to transmit the command to the device so that the device completes the state transition after the operation following the command at time adjusted in accordance with the estimated value.
Arrangements of a control apparatus according to the present invention will be described in detail below with reference to the accompanying drawings.
In view of efficient use of renewable energy, energy efficiency, and energy utilization, distributed power supplies, such as photovoltaics (PV), storage batteries, and electric vehicles (EV), have been given a great importance and widespread. In the balancing market, which is due to be launched, such distributed power supplies may be controlled according to results of transaction. In such a balancing market, not only larger-scale distributed power supplies but also smaller-scale power supplies are to be subjected to transactions. That is, there have been growing needs for controlling the small-scale distributed power supplies (including customers' owned power supplies) in a distributed manner at a higher speed. Under such circumstances, requirements for operating distributed power supplies correctly at designated times draw attention.
Meanwhile, upon start of the fifth generation (5G) mobile communication system and local 5G service, a communication infrastructure with less delay than before is being constructed. In addition, installation of an application executable environment called multi-access edge computing (MEC) in the vicinity of a 5G base station is under consideration. Thus, it is expected that control in a distributed environment using MEC is of greater importance in addition to centralized control in a cloud environment.
Consider that among device groups such as distributed power supplies placed in a distributed manner in a wide area, a designated subset of a device group is remotely controlled simultaneously at given time from a cloud environment. A control command (a packet for transmitting a control command) typically reaches the devices at different times because of a difference in communication delay. Thus, simply transmitting the control command through broadcasting may result in a failure in controlling the devices to start operating at the same time.
It is possible to transmit the control command so that it arrives at the respective devices at substantially the same timing by adjusting the control-command transmission timing for each of the devices in view of communication delay. However, it may take a time (operation delay time) for some devices to complete a transition to a designated operation state (switching to a desired operation) from receipt of the control command.
Such operation delay time may vary depending on a difference in device type or model, details of the control command, and previous operation states of the devices.
When the device to be controlled is a storage battery and the storage battery is controlled to change discharge power to X(W), for example, the storage battery typically requires an operation delay time to change discharge power to a value X(W) (completion of switching to a desired operation) from receipt of a control command for the change.
Further, even with respect to the same control command (for example, a control command for changing discharge power), the operation delay time for completion of a transition to a desired operation state may differ depending on the operation state before receipt of the control command.
Examples of the operation state include a discharge state, a charge state, and a stop state. The operation states may be distinguished in consideration of the amount of power stored in the storage battery. For example, even if the previous operation states are the same discharge state, the operation delay time may differ in shifting the amount of power from X1 (W) to X (W) and in shifting the amount of power from X2 (W) to X (W).
Storage batteries of the same model are considered to have uniform characteristics. However, they may differ in operation delay time depending on the surrounding environments (such as temperature, climate, cold district, indoor, outdoor) and their usage conditions (e.g., period of use) .
Such variations in the operation delay time cause difficulty in implementing an operation instruction for the devices to transition to a desired operation state at desired time from the cloud environment.
With respect to one's own products, the operation delay time caused by a control command or a difference in states can be known in advance from the specification or test results. In this case, it is possible to adjust the control-command transmission timing in view of the operation delay time. However, as to devices manufactured by another manufacturer, for example, it may not be possible to know information on the operation delay time in advance. Even the operation delay time of one's own product may differ from the actual result due to an influence of an installation environment, as described above.
Thus, it is desirable to establish a system that implements supervisory control over devices (such as distributed power supplies) installed in a distributed manner, to be able to manage and estimate a delay time of each of the devices so as to accurately control the devices to transition (switch) to another operation at designated time in consideration of communication delay and operation delay.
Control apparatuses according to the following arrangements individually and dynamically estimate or predict the operation delay time of intended devices, to control the devices in view of the delay time. Thereby, the control apparatuses can accurately control the devices to make a state transition (switch operation states) at designated time. First Arrangement
FIG. 1 is a diagram illustrating an exemplary overall configuration of a communication system including a control apparatus according to a first arrangement. As illustrated in FIG. 1, in the communication system of the present arrangement the control apparatus 100 is connected to devices 300a to 300d as a subject of control via relay apparatuses 200a and 200b through a network. The network is, for example, the Internet but may be of any other form. The network may be a wired network, a wireless network, or a combination thereof.
The control apparatus 100 is, for example, a server built up in a cloud environment. The relay apparatuses 200a and 200b are, for example, MECs installed in the vicinity of a 5G base station. The relay apparatuses 200a and 200b are simply referred to as relay apparatus or apparatuses 200 unless they are to be distinguished from each other. The number of the relay apparatuses 200 is not limited to two, and may be one or three or more.
The devices 300a to 300d are to be controlled by the control apparatus 100. FIG. 1 illustrates distributed power supplies as an example of the devices 300a to 300d. The device 300a serves as a solar battery. The devices 300b and 300d serve as storage batteries. The device 300c serves as a charger and discharger for charge and discharge with respect to an electric vehicle. The devices 300a to 300d are simply referred to as device or devices 300 unless they are to be distinguished from each other. The number of the devices 300 is not limited to four, and may be two or three or five or more.
FIG. 2 is a diagram illustrating an exemplary overall configuration of another communication system including the control apparatus 100 according to the first arrangement. FIG. 2 illustrates an exemplary configuration including gateways (GW) installed inside a building or a home as relay apparatuses 200 (200c and 200d).
In both the communication systems in FIGS. 1 and 2, the relay apparatuses 200 receive a control command from the control apparatus 100 and then transfer the control command to the devices 300. A communication protocol between the control apparatus 100 and the relay apparatuses 200 may be the same as or different from a communication protocol between the relay apparatuses 200 and the devices 300.
The communication protocol may be a virtual private network (VPN) protocol. As for the communication system in FIG. 2, the communication protocol between the gateways (relay apparatuses 200) and the devices 300 may be exemplified by ECHONET Lite (registered trademark), which is a control standard for an power management system (EMS).
The system configurations in FIGS. 1 and 2 are merely exemplary, and the communication systems may have any other configuration. For example, the function of the control apparatus 100 in FIG. 2 may be implemented by an MEC. The communication systems in FIGS. 1 and 2 are configured on the premise that the devices 300 include no function of establishing direct secure communications with the control apparatus 100. The devices 300 may include a function of secure communications with the control apparatus 100 to communicate with the control apparatus 100 without the relay apparatuses 200. In this case, the difference between the former and the latter is in omission of the processing time of the relay apparatuses 200. The following will mainly describe the communication system including the relay apparatuses 200 by way of example.
FIG. 3 is a block diagram illustrating an exemplary configuration of the apparatuses and the device according to the first arrangement. As illustrated in FIG. 3, the control apparatus 100 includes a storage 121, a device controller 101, a calculator 102, a communication controller 103, and an updater 104.
The storage 121 stores therein various types of information for use in various types of processing to be executed by the control apparatus 100. For example, the storage 121 stores therein pieces of classification information in association with pieces of calculation information. The classification information represents at least one of the type of a control command generated by the device controller 101 and the type of a state transition of the device 300 in operation following the control command. The calculation information represents an estimated value of an operation delay time or a calculation formula for calculating the estimated value. The information stored in the storage 121 will be described in detail later.
The storage 121 can include any general-purpose storage medium, such as flash memory, a memory card, a random access memory (RAM), a hard disk drive (HDD), and an optical disk.
The device controller 101 serves to control the operations of the devices 300. For example, the device controller 101 generates a control command for controlling the operations of the devices 300. The control command may be any command as long as it is for use in controlling the operations of the devices 300. With respect to the devices 300 being distributed power supplies, the device controller 101 may generate, for example, the following control commands:

a command for turning on or off the power of the devices 300;
a command for changing a designated value of power (charging power or discharge power); and
a command for changing the states (e.g., discharge state, charge state, and stop state) of the devices 300.

The calculator 102 serves to calculate an estimated value of the operation delay time for each of the devices 300. For example, the calculator 102 calculates an estimated value of the operation delay time according to the classification information corresponding to the control command generated by the device controller 101. Specifically, the calculator 102 calculates an estimated value of the operation delay time according to the calculation information associated with the classification information of the control command as generated, of the calculation information stored in the storage 121.
The communication controller 103 serves to control communications between the control apparatus 100 and external apparatuses, such as the relay apparatuses 200. For example, the communication controller 103 transmits the control command to the devices 300 via the relay apparatuses 200 such that the devices 300 complete a state transition at desired time after operating by the control command. The communication controller 10 adjusts, for example, a transmission time in consideration of the delay time so that the devices 300 complete a state transition at desired time, and transmits the control command to the devices 300 at the transmission time.
The device controller 101 may adjust the transmission time and control the communication controller 103 to transmit the control command at the adjusted transmission time. The control apparatus 100 (communication controller 103 or device controller 101) may instruct the relay apparatuses 200 to transmit the control command at the adjusted transmission time, and the relay apparatuses 200 may transmit the control command at the transmission time as instructed.
The delay time includes communication delay time and operation delay time. The communication delay time of each of the devices 300 may be calculated by any method. As an example, the communication delay time can be calculated by the following methods:

M1: calculating the communication delay time from an average value of actual values (history) of the communication delay time acquired through communications with the devices 300;
M2: calculating the communication delay time according to the features (such as communication speed) of the network between the control apparatus 100 and the devices 300.

The updater 104 serves to update the calculation information stored in the storage 121. For example, the updater 104 updates the calculation information with an actual value of the operation delay time and stores the updated calculation information in the storage 121.
The elements (i.e., device controller 101, calculator 102, communication controller 103, and updater 104) are implemented by, for example, one or a plurality of processors. For example, the elements may be implemented by software, that is, by causing a processor such as a central processing unit (CPU) to execute a computer program. The elements may be implemented by hardware, that is, a processor such as a dedicated integrated circuit (IC). The elements may be implemented by a combination of software and hardware. In the case of using multiple processors, each of the processors may implement one or two or more of the elements.
The relay apparatuses 200 each include a communication controller 201. The communication controller 201 serves to control communications with external apparatuses and devices, such as the control apparatus 100 and the devices 300. For example, the communication controller 201 receives and transfers the control command from the control apparatus 100 to the devices 300.
The devices 300 each include a communication controller 301 and an operation controller 302. The communication controller 301 controls communications with external apparatuses, such as the relay apparatus 200. For example, the communication controller 301 controls reception of the control command from the relay apparatus 200 and transmission of a response (response packet) to the control command via the relay apparatus 200. The operation controller 302 serves to control operation of the device 300 in accordance with the control command. For example, with respect to the device 300 being a distributed power supply, the operation controller 302 controls the device 300 to power on and off, change a designated power value, and change the state in accordance with the control command.
As with the elements of the control apparatus 100, the elements of the relay apparatuses 200 and the devices 300 can be implemented by, for example, one or a plurality of processors.
Next, the delay time in transmission of the control command will be described. FIG. 4 is a diagram illustrating a communication delay and an operation delay in the control command when issued from the control apparatus 100 to the device 300 via the relay apparatus 200.
For the sake of simple explanation, FIG. 4 omits illustrating a time taken for a process from when the device controller 101 generates a control command to instruct the communication controller 103 to transmit the control command to when the communication controller 103 outputs the control command to the network with the relay apparatus 200 (as indicated by the dotted arrows in the drawing). FIG. 4 also omits illustrating a time taken for internal processing of the control apparatus 100 after receiving a response to the control command from the network with the relay apparatus 200.
In FIG. 4, T1 represents time at which the control apparatus 100 transmits the control command, and T2 represents time at which the relay apparatus 200 receives the control command. The communication delay time between T1 and T2 is defined as Δt1 (= T2 - T1).
Δt2 represents a processing time taken for the relay apparatus 200 to convert and transfer the control command to the device 300 to be controlled.
T3 represents time at which the relay apparatus 200 transmits the control command. T4 represents time at which the device 300 receives the control command. The communication delay time between T3 and T4 is defined as Δt3 (= T4 - T3).
Δt4 represents an operation delay time from the device 300's receiving the control command to completing a state transition (switching) to an operation state as instructed by the control command.
As illustrated in FIG. 4, for example, the device 300 (communication controller 301) returns a response packet at time T5 immediately after completing the transition. The relay apparatus 200 receives the response packet after elapse of a communication delay time Δt5a.
T6 represents time at which the relay apparatus 200 receives the response packet. Δt6 represents an internal processing time. T7 represents time at which the relay apparatus 200 returns the response packet to the control apparatus 100. The control apparatus 100 receives the response packet after an elapse of a communication delay time Δt7.
T8 represents time at which the control apparatus 100 receives the response packet. The communication delay time Δt7 is defined as T8 - T7.
The communication delay time and the operation delay time occurring from the transmission of the control command from the control apparatus 100 to the device 300 is defined as Δt1 + Δt2 + Δt3, and Δt4, respectively. As described above, the communication delay time can be obtained by, for example, the methods M1 and M2. In the following, the communication delay time is assumed to be constant irrespective of a control command type, for the sake of simple explanation.
In the present arrangement, it is assumed that at least T4 and T5 (or Δt4) among T1, T2, T3, T4, and T5 be added to the response packet with respect to the control command and that the relay apparatus 200 employ a protocol available for the control apparatus 100. For example, the communication controller 301 returns the response packet containing at least T4 and T5 (or Δt4) as a response to the control command, to the control apparatus 100 via the relay apparatus 200.
Thus, the actual value of the operation delay time can be obtained from temporal information added to the response packet. For example, from the response packet containing added temporal information T4 and T5, the updater 104 calculates the actual value of the operation delay time by the formula Δt4 = T5 - T4. From the response packet containing added temporal information Δt4, the updater 10 can use the added value as the actual value of the operation delay time as it is.
A method of indirectly obtaining the time Δt4 when T4 and T5 (or Δt4) are not directly obtainable will be described in a second arrangement.
The control apparatus 100 of the present arrangement individually and dynamically estimates or predicts the operation delay time Δt4 of the devices 300 so as to be able to obtain different values irrespective of differences in the types or models of the devices 300, the control command types, operation states before execution of various commands, characteristics of the devices 300, installation environments, and the usage conditions of the devices 300, for example. The control apparatus 100 then controls the devices 300 to complete an operation-state transition (switching) at designated time, according to the estimated value of the operation delay time.
The following will describe a method of calculating an estimated value of the operation delay time. FIG. 5 is a diagram illustrating exemplary calculation information for use in calculating the estimated value. As illustrated in FIG. 5, the calculation information includes a command type, a plurality of state transitions (ST1 and ST2), an estimated value or a calculation formula for the operation delay time (Δt4) with respect to each of the state transitions, and history data. The number of the state transitions is not limited to two, and may be one or three or more.
The calculation information in FIG. 5 is stored for each piece of identification information (e.g., device ID) for identifying the devices 300, for example. This makes it possible to calculate the operation delay time, which differs even among the devices 300 of the same model depending on, for example, the surrounding environments and/or the usage conditions of the devices 300.
The unit of managing the calculation information is not limited to the above example. The calculation information may be managed for each piece of identification information for identifying the types or models of the devices 300. Alternatively, if the types or models of the devices 300 and the surrounding environments are limited, for example, the calculation information illustrated in FIG. 5 may be managed in common for all the devices 300.
The control apparatus 100 (calculator 102) dynamically estimates or predicts a Δt4 value by referring to the calculation information illustrated in FIG. 5. The control apparatus 100 (updater 104) updates the estimated value or the calculation formula, using history data.
The history data represents an actual Δt4 value calculated at the time of transmission of the corresponding control command. Each time a control command is transmitted, the actual Δt4 value obtained as described above is stored in the storage 121 as the history data.
The updater 104 calculates the estimated value and the calculation formula for the operation delay time Δt4 for each type of the control command and each type of an operation state transition by the control command, by averaging and linear regression of the history data (history data aggregate), and stores the resultant value and formula in the storage 121.
For example, a control command A serves to cause the devices 300 to transition from a power-ON state to a power-OFF state or from a power-OFF state to a power-ON state. The state transition ST1 indicates a transition from the power-ON state to the power-OFF state. xa1 (ms) represents an estimate of the Δt4 value calculated from the history data in this case. The state transition ST2 indicates a transition of a power-OFF state to a power-ON state. xa2 (ms) represents an estimate of the Δt4 value calculated from the history data in this case.
As for the history data containing (ON→OFF: 1650 ms), (OFF→ON: 1956 ms), (ON→OFF: 1672 ms), and (OFF→ON: 1932 ms), the updater 104 can calculate each of the estimated values by, for example, calculating an average value of the history data by the following formulas: $xa 1 = (1650 + 1672) / 2;$
and $xa 2 = (1956 + 1932) / 2.$
The control command A may be divided into a control command A1 for a transition from a power-ON state to a power-OFF state and a control command A2 for a transition from a power-OFF state to a power-ON state for management, for example. In this case, only the estimated value or the calculation formula corresponding to one state transition ST1 is stored for each of the control commands A1 and A2, for example. If the control commands correspond to state transitions one by one, the calculation information can exclude the command-type column or the state-transition column. This signifies that the control command type and the state transition type can be interpreted as substantially the same.
A control command B serves to increase or decrease a control value relating to the operation of the device 300 by predefined increments and decrements. The state transition ST1 of the control command B indicates an increase in the control value in conformity with a designated value. The state transition ST2 indicates a decrease in the control value in conformity with a designated value.
On the premise that the Δt4 value linearly increase and decrease relative to a designated value, the updater 104 obtains the calculation formula for the estimated value. FIG. 5 illustrates calculation formulas for Δt4 by way of example as below: $Δt 4 = (xb 1 / unit of increase) \times (increase in designated value) + b 1;$
and $Δt 4 = (xb 2 / unit of decrease) \times (decrease in designated value) + b 2.$
xb1 (ms) represents the time taken for increasing the control value per unit of increase. b1 represents the initial value of an increase. xb2 (ms) represents the time taken for decreasing the control value per unit of decrease. b2 represents the initial value of a decrease.
Assume that the unit of increase and the unit of decrease be both one and that the history data contain (5→8: 453 ms), (8→3: 212 ms), (3→10: 1002 ms), and (10→5: 222 ms). For example, "5→8" indicates a designated value increasing from 5 to 8. Thus, at the time of increasing, (increase in designated value, Δt4) is obtained as (3, 453) and (7, 1002). At the time of decreasing, (decrease in designated value, Δt4) is obtained as (-5, 212) and (-5, 222). The updater 104 can derive xb1 and b1 or xb2 and b2 by linear regression of these pieces of information.
A control command C serves to cause the device 300 to transition among a plurality of predefined states. FIG. 5 illustrates an example that the device 300 can be placed in three states, α, β, and γ. That is, six state transitions, α→β, β→α, β→γ, γ→β, α→γ, and γ→α, are possible. When the device 300 can be in n states, the number of the state transitions will be _nP₂ at maximum. FIG. 5 illustrates only two of the six state transitions; however, in response to another state transition, the updater 104 also stores the estimated value or the calculation formula with respect to this state transition.
The updater 104 calculates the estimated value or the calculation formula from the history data for each of the state transitions. From the history data containing (α→β: 242 ms), (β→γ: 321 ms), (γ→α: 294 ms), (α→β: 232 ms), and (β→γ: 319 ms), the updater 104 can calculate, for example, the estimated values as average values of the history data as below: $xc 1 = (242 + 232) / 2;$
and $xc 2 = (321 + 319) / 2.$
xc1 (ms) represents an estimate of the Δt4 value calculated from the history data in a state transition from α to β. xc2 (ms) represents an estimate of the Δt4 value calculated from the history data in a state transition from β to γ.
A control command D serves to designate a control value relating to the operation of the device 300. The state transition ST1 as to the control command D indicates an increase in the control value in conformity with a designated value. The state transition ST2 indicates a decrease in the control value in conformity with a designated value. The control command D causes the control value to shift from a current state x_current to a new state x_new.
On the premise that the Δt4 value increase or decrease relative to a designated value in accordance with an approximation function, the updater 104 obtains the calculation formula for the estimated value. FIG. 5 illustrates calculation formulas for Δt4, as below: $Δt 4 = f (x_current, x_new);$
and $Δt 4 = g (x_current, x_new) .$
The updater 104 models the approximation function using, for example, a learning curve for use in machine learning, and samples the history data as training data to obtain the approximation function. f() represents the approximation function for increasing the control value. g() represents the approximation function for decreasing the control value.
Such a modeling method using an approximation function is applicable to a situation that the Δt4 value cannot be estimated from history data by an average value or linear regression. Such a method is, for example, applicable to modeling of a situation that a difference occurs in increase rate of the operation delay time during a shift in the control value from 1 to 2 and during a shift in the control value from 2 to 4.
A control command E serves to cause the device 300 to make a state transition. The control command E also serves to distinguish states of an element differing from the element that makes a state transition, in order to calculate the estimated value or the calculation formula.
The state transition ST1 as to the control command E indicates a transition from an operation state "s" (for example, charging state) to an operation state "t" (for example, discharge state) during the power-ON state. xe1 (ms) represents an estimate of the Δt4 value calculated from the history data in this case. The state transition ST2 indicates a transition from the operation state "s" (for example, charging state) to the operation state "t" (for example, discharge state) during the power-OFF state. xe2 (ms) represents an estimate of the Δt4 value calculated from the history data in this case.
In the same transitions from the operation state "s" to the operation state "t", the operation delay time may differ due to a power state being another element. In consideration of such a situation, the calculation information as to the control command E is calculated for each of the state transitions between states including a plurality of elements. The number of power states being another element is two so that with the number of possible operation states being m, the number of the state transitions will be 2 × _mP₂ at maximum. FIG. 5 illustrates only two state transitions; however, in response to occurrence of another state transition, the updater 104 also stores the estimated value or the calculation formula for this state transition.
From the history data containing (ON, s→t: 234 ms), (OFF, t→s: 242 ms), (OFF, s→t: 442 ms), (ON, s→t: 242 ms), and (OFF, s→t: 452 ms), the updater 104 can calculate, for example, the estimated values as average values of the history data, as below: $xe 1 = (234 + 242) / 2;$
and $xe 2 = (442 + 452) / 2.$
"ON" in (ON, s→t: 234 ms), for example, indicates a power state being an element differing from the state transition (s→t).
Each time history data is added, for example, the updater 104 updates the estimated value or the calculation formula for the corresponding state transition. In calculating the estimated value from an average value, the updater 104 adds an added value of the history data to the total value of the history data as of now and divides the resultant value by a value obtained by adding one to the total number of the pieces of history data, to thereby calculate a new estimated value. In obtaining the calculation formula for the estimated value by linear regression, the updater 104 recalculates a regression coefficient by adding the added value of the history data.
In obtaining the approximation function as the calculation formula, the updater 104 adds the added value of the history data to sampling values and learns the approximation function again. In this manner, the updater 104 can enhance the estimated value and the calculation formula in terms of accuracy.
Thus, the control apparatus 100 (updater 104) continuously updates the estimated value and the calculation formula of the operation delay time with respect to each state transition in each control command for the purpose of enhancing the accuracy of the estimated value and the calculation formula. When the estimated value and the calculation formula become stable through repetitions of the update process, the control apparatus 100 may stop updating. After stop of the updating, the estimated value or the calculation formula stored in the storage 121 is regarded as a fixed value or formula. This makes it possible to estimate the operation delay time at higher speed.
In response to detection of an outlier greatly different from other values as an actual value (history data) of the operation delay time, the control apparatus 100 may execute preprocessing (filtering) to exclude the outlier before storing in the storage 121.
Immediately after start of the control over the device 300, for example, there may be no available history data corresponding to the various control commands. In such a case the control apparatus 100 may use a predefined default value as the estimated value of the operation delay time. In the case of no history data corresponding to a given control command (state transition), the control apparatus 100 may obtain the estimated value or the calculation formula with reference to existing history data of another state transition. In such a case, it may be expected that the device 300 cannot start a designated operation at correct time. In view of this, it is desirable to transmit various control commands a plurality of times to accumulate history data as a preparation for starting the control, thereby deriving an initial estimated value or calculation formula.
The calculator 102 calculates an estimate of the Δt4 value, referring to the estimated value or the calculation formula as obtained in the above-described manner. For example, the calculator 102 acquires an estimated value or a calculation formula corresponding to a control command type and a state-transition type to be transmitted, from the calculation information stored in the storage 121. After acquiring the calculation formula, the calculator 102 calculates an estimate of the Δt4 value by the calculation formula as acquired.
Next, control processing by the control apparatus 100 of the present arrangement as configured above will be described. FIG. 6 is a flowchart illustrating exemplary control processing according to the present arrangement.
The device controller 101 generates a control command for controlling the device 300 (step S101). The calculator 102 calculates an estimated value of an operation delay time corresponding to the type of the control command and a state transition by the control command (step S102).
The communication controller 103 transmits the control command to the device 300 in consideration of the operation delay time and communication delay time, so that the device 300 completes the state transition according to the control command at designated time (step S103).
The updater 104 obtains an actual value (history data) of the operation delay time in accordance with a response from the device 300, and updates the estimated value or the calculation formula stored in the storage 121 with the actual value (step S104).
The communication controller 103 may control the transmission of the control command in consideration of fluctuations or variations in the actual value of the communication delay time. For example, the calculator 102 calculates a fluctuation (such as a dispersion) in the history data in addition to the estimated value or the calculation formula. The communication controller 103 controls the transmission to transmit the control command at timing adjusted by the fluctuation. For example, in the case of a larger fluctuation, the communication controller 103 transmits the control command at earlier timing than in the case of a smaller fluctuation. The communication controller 103 may control the transmission of the control command, considering fluctuations or variations in the actual value of the operation delay time. In this case, the calculation information in FIG. 5 may include a fluctuation time added to the "Estimated value or Calculation formula" column so that the communication controller 103 may adjust the control-command transmission timing by adding the fluctuation time to the estimated value or calculation formula.
Thus, in the first arrangement, the control apparatus 100 can individually and dynamically estimate the operation delay time of the devices in accordance with the control command type or the state-transition type, to control the devices in consideration of the operation delay time. Thereby, the control apparatus 100 can control the operation timing of the devices at higher accuracy.

Second Arrangement

The first arrangement is based on the use of a communication protocol that allows a return of a response containing T4 and T5 (or Δt4) after completion of a state transition. Depending on communication protocols, a return to a response may not be allowed, or a reception response may be returned immediately after receipt of a control command but a response indicating completion of a state transition may not be returned after the state transition.
A second arrangement will describe an estimation of the operation delay time when T4 and T5 (or Δt4) cannot be obtained from a response.
FIG. 7 is a block diagram illustrating an exemplary configuration of apparatuses and a device included in a communication system according to the second arrangement. The communication system of the second arrangement includes a control apparatus 100-2, a relay apparatus 200-2, and a device 300-2.
The control apparatus 100-2 includes a storage 121, a device controller 101, a calculator 102, a communication controller 103, and an updater 104-2. The relay apparatus 200-2 includes a communication controller 201-2. The device 300-2 includes a communication controller 301-2 and an operation controller 302.
The second arrangement differ from the first arrangement in the functions of the updater 104-2 of the control apparatus 100-2, the communication controller 201-2 of the relay apparatus 200-2, and the communication controller 301-2 of the device 300-2. The rest of the elements and functions are substantially the same as those in FIG. 3, which is a block diagram of the control apparatus 100 of the first arrangement. Thus, the elements are denoted by the same reference numerals, and their description is omitted herein.
The communication controller 301-2 differs from the communication controller 301 in the first arrangement in that the communication controller 301-2 transmits a response packet not containing T4 and T5 (or Δt4) as a response to the control command.
The communication controller 201-2 differs from the communication controller 201 in the first arrangement in including a function of transmitting a state confirmation command to the device 300-2. The state confirmation command is for confirming the state of the device 300-2.
The updater 104-2 differs from the updater 104 in the first arrangement in using information substituted for T4 and T5 to calculate the operation delay time Δt4.
In failing to obtain T4 and T5 (or Δt4) from a response, the updater 104-2 can calculate the actual value of the operation delay time by adopting two policies as follows:
First Policy: If the device 300-2 has a function to transmit a notification message about a change in the state of the device 300-2, independently from operating following the control command, the updater 104-2 substitutes time T6', at which the relay apparatus 200-2 (communication controller 201-2) receives this notification message, for T5. In addition, the updater 104-2 substitutes time T3, at which the relay apparatus 200-2 transmits the control command, for T4. That is, the updater 104-2 calculates the operation delay time by the formula Δt4 = T6' - T3.
For example, the communication controller 301-2 may include the function of transmitting the notification message. First Policy is considered as an effective alternative for the relay apparatus 200-2 and the device 300-2 located close to each other, in other words, in the case of slight communication delay and small fluctuations in the communication delay.
Second Policy: If the device 300-2 adopts a communication protocol that returns no response after a state transition, the relay apparatus 200-2 (communication controller 201-2) transmits a state confirmation command for confirming the state of the device 300-2 at regular intervals. The updater 104-2 substitutes time T6", at which the updater 104-2 confirms completion of a state transition of the device 300-2 designated by the control command from a response (an exemplary notification message) to the state confirmation command, for T5. In addition, the updater 104-2 substitutes time T3, at which the relay apparatus 200-2 transmits the control command, for T4. That is, the updater 104-2 calculates the operation delay time by the formula Δt4 = T6" - T3.
As the intervals at which the state confirmation command is transmitted shorten, the accuracy heightens. However, excessive communications may affect the behavior of the device 300-2. In view of this, the relay apparatus 200-2 (communication controller 201-2) may adjust the transmission intervals of the state confirmation command, taking previous Δt4 values into account (i.e., in accordance with the type and details of the control command).
FIG. 8 is a sequence diagram illustrating exemplary control processing according to Second Policy.
The communication controller 103 of the control apparatus 100-2 transmits a control command to the relay apparatus 200-2 (step S201). The communication controller 201-2 of the relay apparatus 200-2 receives and transmits the control command to the device 300-2 (step S202).
The communication controller 301-2 of the device 300-2 transmits a reception response indicating reception of the control command to the relay apparatus 200-2 (step S203).
The operation controller 302 of the device 300-2 starts a state transition in accordance with the control command (step S204). The order of executing step S203 and step S204 is not limited to this order, and these steps may be executed in reverse order or in parallel.
The communication controller 201-2 of the relay apparatus 200-2 transmits a state confirmation command to the device 300-2 (step S205). The communication controller 301-2 of the device 300-2 returns a response indicating the current state of the device 300-2 in response to the state confirmation command (step S206). In the example in FIG. 8, the device 300-2 has not completed a state transition following the control command, therefore, the communication controller 301-2 returns a response indicating non-completion of the state transition, for example.
The operation controller 302 then completes the state transition following the control command (step S207).
The communication controller 201-2 of the relay apparatus 200-2 transmits the state confirmation command to the device 300-2 again (step S208). The communication controller 301-2 of the device 300-2 returns a response indicating the current state of the device 300-2 in response to the state confirmation command (step S209). In the example in FIG. 8, the communication controller 301-2a returns a response indicating completion of the state transition.
The communication controller 201-2 of the relay apparatus 200-2 determines whether to have received a response indicating completion of a desired state transition (step S210). For example, after receiving a response indicating completion of the state transition within a given period, the communication controller 201-2 transmits a response containing time T6'' at which reception of the response is confirmed, to the control apparatus 100-2 (step S211). After receiving no response indicating completion of the state transition within the given period, the communication controller 201-2 determines no receipt of a response (i.e., timeout) and transmits a message indicating no reception to the control apparatus 100-2.
Thus, in the second arrangement, the control apparatus 100-2 can calculate the actual value of the operation delay time by a method different from that in the first arrangement in compliance with the communication protocol in use.
According to the first and second arrangements as described above, it is made possible to accurately control the operation timing of the intended devices.
The following will describe a hardware configuration of the apparatuses and devices (control apparatus, relay apparatus, and devices) according to the first and second arrangements with reference to FIG. 9. FIG. 9 is an explanatory diagram illustrating an exemplary hardware configuration of the apparatuses and devices of the arrangements.
The apparatuses and devices according to the arrangements each include a controller such as a CPU 51, a storage such as a read only memory (ROM) 52 and a RAM 53, a communication interface (I/F) 54 connected to a network to perform communications, and a bus 61 connecting the elements to one another.
Computer programs executed by the apparatuses and devices according to the arrangements is incorporated in advance and provided in the ROM 52, for example.
The computer programs executed by the apparatuses and devices according to the arrangements may be recorded in an installable or executable file format on a computer-readable recording medium such as a compact disc read only memory (CD-ROM), a flexible disk (FD), a compact disc recordable (CD-R), and a digital versatile disc (DVD), and be provided as a computer program product.
Alternatively, the computer programs executed by the apparatuses and devices according to the arrangements may be stored on a computer connected to a network, such as the Internet, and be provided being downloaded via the network. The computer programs executed by the apparatuses and devices according to the arrangements may be provided or distributed via a network, such as the Internet.
The computer programs executed by the apparatuses and devices according to the arrangements cause a computer to function as the respective elements of the apparatuses and devices. In this computer, the CPU 51 can load and execute the computer programs from the computer-readable recording medium onto a main storage.
The present invention aims to provide a control apparatus, a control method, a computer-readable medium, and a communication system that can control the operation timing of intended devices accurately.
While certain arrangements have been described, these arrangements have been presented by way of example only, and are not intended to limit the scope of the claims. Indeed, the apparatuses and systems described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the apparatuses and systems described herein may be made.
Example 1. A control apparatus includes a device controller configured to generate a command for controlling operation of an intended device; a calculator configured to calculate an estimated value of an operation delay time according to classification information representing at least one of a type of the command and a type of a state transition of the device in operation following the command, the operation delay time being a length of time from when the device receives the command to when the device completes a state transition after the operation following the command; and a communication controller configured to transmit the command to the device so that the device completes the state transition after the operation following the command at time adjusted in accordance with the estimated value.
Example 2. The control apparatus according to Example 1 further includes a storage configured to store therein the classification information and calculation information in association with each other, the calculation information representing the estimated value or a calculation formula for calculating the estimated value. The calculator calculates the estimated value using the calculation information associated with the classification information representing at least one of the type of the command and the type of the state transition of the device in operation following the command.
Example 3. The control apparatus according to Example 2 further includes an updater configured to update the calculation information with an actual value of the operation delay time to store the calculation information in the storage.
Example 4. In the control apparatus according to Example 3, the updater obtains the actual value of the operation delay time from temporal information contained in a response transmitted from the device with respect to the command.
Example 5. In the control apparatus according to Example 3, the updater obtains the actual value of the operation delay time according to time at which the updater has received a notification message as a response to the state confirmation command, the notification message indicating that the device has completed the state transition after the operation following the command.
Example 6. In the control apparatus according to Example 1, the communication controller transmits the command at time adjusted in accordance with a communication delay time and the estimated value, the communication delay time being a length of time from transmission of the command to receipt of the command by the device.
Example 7. In the control apparatus according to Example 1, the calculator calculates the estimated value according to identification information and the classification information, the identification information being for identifying the device or a type of the device.
Example 8. A control method includes generating a command for controlling operation of an intended device; calculating an estimated value of an operation delay time according to classification information representing at least one of a type of the command and a type of a state transition of the device in operation following the command, the operation delay time being a length of time from when the device receives the command to when the device completes a state transition after the operation following the command; and transmitting the command to the device so that the device completes the state transition after the operation following the command at time adjusted in accordance with the estimated value.
Example 9. A computer readable medium includes instructions which, when executed by a computer, cause the computer to perform generating a command for controlling operation of an intended device; calculating an estimated value of an operation delay time according to classification information representing at least one of a type of the command and a type of a state transition of the device in operation following the command, the operation delay time being a length of time from when the device receives the command to when the device completes a state transition after the operation following the command; and transmitting the command to the device so that the device completes the state transition after the operation following the command at time adjusted in accordance with the estimated value.
Example 10. A communication system includes a relay apparatus connected to a device to be controlled; and a control apparatus connected to the relay apparatus. The control apparatus includes a device controller configured to generate a command for controlling operation of the device; a calculator configured to calculate an estimated value of an operation delay time according to classification information representing at least one of a type of the command and a type of a state transition of the device in operation following the command, the operation delay time being a length of time from when the device receives the command to when the device completes a state transition after the operation following the command; and a communication controller configured to transmit the command to the device so that the device completes the state transition after the operation following the command at time adjusted in accordance with the estimated value. The relay apparatus is configured to receive and transmit the command from the control apparatus to the device.
Example 11. In the communication system according to Example 10, the control apparatus further includes a storage configured to store therein the classification information and calculation information in association with each other, the calculation information representing the estimated value or a calculation formula for calculating the estimated value; and an updater configured to update the calculation information with an actual value of the operation delay time to store the calculation information in the storage. The calculator calculates the estimated value using the calculation information associated with the classification information representing at least one of the type of the command and the type of the state transition of the device in operation following the command. The relay apparatus transmits a state confirmation command to the device after transmitting the command, the state confirmation command being for confirming a state of the device. The updater obtains the actual value of the operation delay time according to time at which the updater has received a notification message as a response to the state confirmation command. The notification message indicates that the device has completed the state transition after the operation following the command.

Claims

A control apparatus (100; 100-2) comprising:
a device controller (101) configured to generate a command for controlling operation of an intended device (300; 300-2) ;

a calculator (102) configured to calculate an estimated value of an operation delay time according to classification information representing at least one of a type of the command and a type of a state transition of the device (300; 300-2) in operation following the command, the operation delay time being a length of time from when the device receives the command to when the device completes a state transition after the operation following the command; and

a communication controller (103) configured to transmit the command to the device (300; 300-2) so that the device completes the state transition after the operation following the command at time adjusted in accordance with the estimated value.
The control apparatus (100; 100-2) according to claim 1, further comprising:
a storage (121) configured to store therein the classification information and calculation information in association with each other, the calculation information representing the estimated value or a calculation formula for calculating the estimated value, wherein

the calculator (102) calculates the estimated value using the calculation information associated with the classification information representing at least one of the type of the command and the type of the state transition of the device (300; 300-2) in operation following the command.
The control apparatus (100; 100-2) according to claim 2, further comprising:
an updater (104; 104-2) configured to update the calculation information with an actual value of the operation delay time to store the calculation information in the storage (121).
The control apparatus (100; 100-2) according to claim 3, wherein
the updater (104; 104-2) obtains the actual value of the operation delay time from temporal information contained in a response transmitted from the device (300; 300-2) with respect to the command.
The control apparatus (100; 100-2) according to claim 3, wherein
the updater (104; 104-2) obtains the actual value of the operation delay time according to time at which the updater has received a notification message as a response to the state confirmation command, the notification message indicating that the device (300; 300-2) has completed the state transition after the operation following the command.
The control apparatus (100; 100-2) according to claim 1, wherein
the communication controller (103) transmits the command at time adjusted in accordance with a communication delay time and the estimated value, the communication delay time being a length of time from transmission of the command to receipt of the command by the device.
The control apparatus (100; 100-2) according to claim 1, wherein
the calculator (102) calculates the estimated value according to identification information and the classification information, the identification information being for identifying the device (300; 300-2) or a type of the device.
A control method comprising:
generating a command for controlling operation of an intended device (300; 300-2) (S101);

calculating an estimated value of an operation delay time according to classification information representing at least one of a type of the command and a type of a state transition of the device (300; 300-2) in operation following the command, the operation delay time being a length of time from when the device receives the command to when the device completes a state transition after the operation following the command (S102); and

transmitting the command to the device (300; 300-2) so that the device completes the state transition after the operation following the command at time adjusted in accordance with the estimated value (S103).
A computer readable medium comprising instructions which, when executed by a computer, cause the computer to perform:
generating a command for controlling operation of an intended device (300; 300-2) (S101);

calculating an estimated value of an operation delay time according to classification information representing at least one of a type of the command and a type of a state transition of the device (300; 300-2) in operation following the command, the operation delay time being a length of time from when the device receives the command to when the device completes a state transition after the operation following the command (S102); and

transmitting the command to the device (300; 300-2) so that the device completes the state transition after the operation following the command at time adjusted in accordance with the estimated value (S103).
A communication system comprising:
a relay apparatus (200; 200-2) connected to a device (300; 300-2) to be controlled; and

a control apparatus connected to the relay apparatus (200; 200-2), wherein

the control apparatus comprises:
a device controller (101) configured to generate a command for controlling operation of the device (300; 300-2) ;

a calculator (102) configured to calculate an estimated value of an operation delay time according to classification information representing at least one of a type of the command and a type of a state transition of the device (300; 300-2) in operation following the command, the operation delay time being a length of time from when the device receives the command to when the device completes a state transition after the operation following the command; and

a communication controller (103) configured to transmit the command to the device (300; 300-2) so that the device completes the state transition after the operation following the command at time adjusted in accordance with the estimated value, and

the relay apparatus (200; 200-2) is configured to receive and transmit the command from the control apparatus (100; 100-2) to the device (300; 300-2).
The communication system according to claim 10, wherein the control apparatus further comprises:
a storage (102) configured to store therein the classification information and calculation information in association with each other, the calculation information representing the estimated value or a calculation formula for calculating the estimated value; and

an updater (104; 104-2) configured to update the calculation information with an actual value of the operation delay time to store the calculation information in the storage (121),

the calculator (102) calculates the estimated value using the calculation information associated with the classification information representing at least one of the type of the command and the type of the state transition of the device (300; 300-2) in operation following the command,

the relay apparatus (200; 200-2) transmits a state confirmation command to the device (300; 300-2) after transmitting the command, the state confirmation command being for confirming a state of the device, and

the updater (104; 104-2) obtains the actual value of the operation delay time according to time at which the updater has received a notification message as a response to the state confirmation command, the notification message indicating that the device (300; 300-2) has completed the state transition after the operation following the command.